HashSet in Java Collections Framework

🚀 HashSet in Java Collections Continuing my journey into Set-based collections, I explored HashSet, one of the most widely used data structures for storing unique elements efficiently. 🔹 What is HashSet? HashSet is a class in the Java Collections Framework that stores unique elements. It does not maintain insertion order. Internally backed by a HashMap (Hash Table). 🔹 Key Properties ❌ No insertion order (unordered) ❌ No duplicates allowed ✅ Allows only one null value ✅ Supports heterogeneous data ✅ Fast operations using hashing 🔹 Internal Working Uses Hashing mechanism Data stored in buckets (HashMap structure) Performance depends on: hashCode() equals() 👉 Important: To avoid duplicates, Java uses: hashCode() → to locate bucket equals() → to compare objects 🔹 Constructors HashSet() HashSet(int capacity) HashSet(Collection c) HashSet(int capacity, float loadFactor) ⭐ 👉 Default load factor = 0.75 (important for performance tuning) 🔹 Important Methods add(E e) remove(Object o) contains(Object o) size() isEmpty() clear() iterator() forEach() 🔹 Traversal (Accessing Elements) For-each loop Iterator Stream (Java 8) ❌ No indexing → Traditional for loop not applicable ListIterator not supported 🔹 Performance Add / Remove / Search → O(1) (average) Very fast for lookup operations 🔹 When to Use HashSet? When uniqueness is required When order is not important When you need fast searching/filtering Removing duplicates from collections 🔥 Key Difference (HashSet vs List) HashSet → No order, no duplicates List → Maintains order, allows duplicates 🔹 Learning Outcome Strong understanding of Set behavior Clear idea of hashing & performance Importance of equals() & hashCode() Choosing correct DS based on requirement 🙌 Special thanks to the amazing trainers at TAP Academy: kshitij kenganavar Sharath R MD SADIQUE Bibek Singh Vamsi yadav Hemanth Reddy Harshit T Ravi Magadum Somanna M G Rohit Ravinder TAP Academy Grateful to Tap Academy for strengthening my core Java and data structure concepts 🚀 #TapAcademy #Week13Learning #CoreJava #CollectionsFramework #HashSet #DataStructures #JavaFundamentals #LearningByDoing #FullStackJourney #VamsiLearns

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